Piers are potentially dangerous places. Containers, equipment, cargo, ropes, chains and other items are deposited on piers. Some of these items are transferred from watercraft. Other items are awaiting transfer to watercraft. The remainder of items on a pier include equipment for transferring materials to and from watercraft and items for servicing watercraft. Most of these items are moved frequently and are only in one location on a pier temporarily. The edge or edges of a pier are often free of obstructions that could hinder access to or from a watercraft or that could prevent people from falling into the water.
A deck of a watercraft may be small, and is often a temporary storage area for ropes, nets, chains and other items relating to the operation or use of a watercraft. Railings and cables to keep people from falling from the deck of a watercraft are frequently minimal or non-existent.
Mooring cleats are attached to the edges of both piers and decks to receive lines and secure watercraft to piers. Because these cleats are on the edge of both piers and watercraft adjacent to the water, they indicate a location relative to the water and potential danger. During daylight hours and periods of good visibility, mooring cleats are easy to see and clearly indicate the location of a boundary that should not be crossed unintentionally.
During periods of darkness and periods of poor visibility it is difficult or even impossible to see mooring cleats. When the cleats cannot be seen, a person could trip on them and fall. A person could also walk off the edge of a pier or the side of a watercraft if a restraining system is not provided.
Piers and watercraft decks are not always well illuminated at night. Bright lights can make it difficult for the helmsman of an approaching watercraft to see what is under or to the rear of a bright light. Illumination on some watercraft is limited. It can be difficult to maintain electrical systems in a marine environment. The helmsman also needs to eliminate any artificial illumination that might interfere with his vision and ability to see other watercraft, piers, and other possible obstructions.